1. Technical Field
The present disclosure relates to a printer that prints on continuous paper, and relates more particularly to a continuous paper conveyance device having means of detecting if continuous paper is jammed in the conveyance path, and to a printer having the conveyance device.
2. Related Art
Printers that print on fanfold paper or other continuous paper and use a tractor and paper feed roller as the conveyance mechanism that conveys the continuous paper are known from the literature. See, for example, Japanese Unexamined Patent Appl. Pub. JP-A-2011-168365. The printer disclosed in JP-A-2011-168365 has sensors (paper detectors) located just before the paper feed roller for detecting the leading end of the continuous paper supplied from the tractor side. This printer detects the presence of continuous paper before the paper feed roller based on output from these sensors, and controls conveying the continuous paper based on the result of detecting continuous paper.
Because sensors for detecting paper are located on the upstream side of the printhead in the printer taught in JP-A-2011-168365, problems such as a paper jam occurring upstream from the printhead can be detected when the paper does not reach the position of the sensors. More specifically, paper jams that occur before the paper is supplied to the printing position can be detected. When an inkjet head is used as the printhead and a paper jam occurs between the inkjet head and the platen, the printhead can be damaged by contact between the printhead and the paper. Detecting a paper jam at the printing position and removing the jammed paper as quickly as possible is therefore necessary.
However, after the paper has entered the conveyance path and printing has started, paper jams cannot be detected from the sensor signals output by the sensors that detect the presence of paper as described in JP-A-2011-168365.
When the paper exit of the printer is blocked so that the continuous paper cannot be discharged and the paper jams at the downstream end of the conveyance path, there is a delay until the downstream paper jam affects the upstream side, and the sensors on the upstream side of the printing position cannot quickly detect paper jams occurring on the downstream side. If paper jam detection is delayed, the stuck paper cannot be quickly removed, and preventing damage caused by the inkjet head moving while paper is jammed is difficult.